CCEA A-Level Economics 4410
Key Economic Concepts
The Basic Economic Problem of Scarcity and Choice
Demand and Supply in Product Markets
Markets and Equilibrium
Elasticity of Demand and Supply
Factor Markets: Labour
Market Failures and Imperfections
Government Intervention in Markets
The Circular Flow of Income
Measuring National Income
Aggregate Demand
Aggregate Supply
Macroeconomic Equilibrium
Macroeconomic Objectives
Inflation
Unemployment
Economic Growth
Fiscal Policy and Its Effects
Monetary Policy
Supply-Side Policies
Exchange Rates and the National Economy
Short Run Versus Long Run
Business Objectives
Business Growth
Measuring Markets
Analysing Market Structures
Perfect Competition
Monopoly
Monopolistic Competition
Oligopoly
Contestable Markets
Competition Policy
Trade and Globalisation
Economic Development
Balance of Payments
Exchange Rate Systems and Competitiveness
European Union (EU)
Monetary Policy and the Financial Sector
Fiscal Deficits and the National Debt
Macroeconomic Policies and Objectives in a Global Economy
Quantitative Skills in Economics
Analysing Market Structures
Efficiency across the market structures
- 1 thing to know
- Unit A2 1
Overview
Allocative efficiency and state the condition that identifies it, perfectly competitive firm allocatively efficient in long-run equilibrium and monopoly achieve neither allocative nor productive efficiency.
What you need to know
Answer each one before you reveal it.
Questions from this subtopic
Each one with the model answer underneath.
- 1
Define allocative efficiency and state the condition that identifies it.
Model answer
Allocative efficiency is reached when resources are distributed so that no reallocation could make anyone better off without making someone else worse off, which for a single market means output is at the level society values most. The condition is that price equals marginal cost. Price measures the value the marginal buyer places on the last unit and marginal cost measures the value of the resources used to make it, so equality means the last unit produced is worth exactly what it cost society.
- 2
Define productive efficiency and state where it occurs on a cost curve diagram.
Model answer
Productive efficiency means output is produced at the lowest possible average cost, so no resources are wasted in making it. It occurs at the minimum point of the average total cost curve, which is also the point where the marginal cost curve cuts average total cost from below. A firm producing at any other output is using more resources per unit than it needs to.
- 3
A firm has fixed costs of £60 and total variable costs of 40, 64, 78, 96, 130 and 186 at outputs of one to six units. At which output is it productively efficient?
Model answer
Total cost is 100, 124, 138, 156, 190 and 246, so average total cost is 100, 62, 46, 39, 38 and 41. The minimum is £38 at five units, so five units is the productively efficient output. The marginal cost figures confirm it: marginal cost is £34 at the fifth unit, below the £39 average, which pulls the average down, and £56 at the sixth, above the £38 average, which pushes it back up.
- 4
A monopolist faces P = 100 − 2Q and has total costs TC = 30 + 10Q + Q². Show that its chosen output is not allocatively efficient, and find the output that would be.
Model answer
It produces where marginal revenue equals marginal cost: 100 − 4Q = 10 + 2Q gives Q = 15, P = £70. Marginal cost at that output is 10 + 2(15) = £40, so price exceeds marginal cost by £30 and the last unit is worth far more to buyers than it costs to make. Allocative efficiency requires price to equal marginal cost: 100 − 2Q = 10 + 2Q gives 90 = 4Q, so Q = 22.5 units at a price of £55. The monopolist therefore under-produces by 7.5 units.
- 5
For a monopolist with demand P = 100 − 2Q and costs TC = 30 + 10Q + Q², calculate the deadweight welfare loss and describe the area it occupies on the diagram.
Model answer
The firm produces 15 units at £70, where marginal cost is £40; the allocatively efficient output is 22.5 units at £55, where price and marginal cost are both £55. The loss is the triangle bounded above by the average revenue curve, below by the marginal cost curve, and on the left by the vertical line at 15 units, closing at the point where the two curves meet at 22.5 units. Its vertical side runs from £40 to £70, a height of £30, and its horizontal base runs from 15 to 22.5 units, a length of 7.5. The area is ½ × 7.5 × 30 = £112.50.
- 6
Why is a perfectly competitive firm allocatively efficient in long-run equilibrium?
Model answer
The firm's demand curve is horizontal at the market price, so marginal revenue equals price. It maximises profit where marginal cost equals marginal revenue, and therefore where marginal cost equals price. That is precisely the allocative efficiency condition, and it holds in the short run as well as the long run. What the long run adds is that entry has pushed price down to minimum average total cost, so the firm is productively efficient at the same time.
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